The invention relates to an arrangement comprising a ureter tube, (ureter stant), a mandrin having an outer shaft and an inner shaft which latter is longitudinally movable relatively to the outer shaft, and an auxiliary tube, the ureter tube and auxiliary tube being slidable onto the mandrin, and the mandrin and the ureter tube being releasably connected with each other. Such art arrangement is the subject matter of German Laid-open Application DE-OS 38 24 244, corresponding to my U.S. patent application Ser. No. 468,017, filed Jan. 22, 1990 now U.S. Pat. No. 5,074,849 or the earlier German Patent Application P 39 00 738.3, corresponding to my U.S. patent application Ser. No. 462,221, filed Jan. 9, 1990 now abandoned. In this arrangement ureter tube, mandrin and auxiliary tube form a functional unit which, in order to improve introduction, makes possible forward as well as rearward movements or rotational movements of the ureter tube and also curving of the ureter tube tip and, upon proper placement of the ureter tube permits ready removal of the mandrin and the auxiliary tube without problems. Furthermore, as to the prior art mention should be made of DE-OS 38 24 244. This Laid-open Application provides a releasable screw connection between mandrin and ureter tube (called "drainage tube" in this earlier publication). Such a screw connection may take place between an outer thread of the mandrin tip and a cooperating thread in the tip range of the interior of the ureter tube. In another embodiment of DE-OS 38 24 244 provisions are made so that the ureter tube, in the range of its tube end adjoining the auxiliary tube, has an inner thread which is engaged by an outer thread of the mandrin. In both of the above instances the thread of the ureter tube can either be directly provided in its material or in a little tube which is firmly connected with the ureter tube. Moreover, it is possible in these embodiments that the end of the ureter tube near the end of the auxiliary tube is guarded against rotational movement with respect to the auxiliary tube tip by means of projections and recesses engaging the latter. In this manner, in the process of establishing or releasing the screw connection between mandrin and ureter tube longitudinal displacements or rotational movements between ureter tube and auxiliary tube are prevented. Finally, DE-OS 38 24 244 provides as a further solution that the auxiliary-tube-adjoining end of the ureter tube has one or more obliquely extending recesses, and that the auxiliary tube has one or more obliquely extending projections which are somewhat smaller than the recesses and may be engaged with each other as a rotation preventing means. The mandrin tip in this instance has a section with an angular cross-sectional profile which extends into a correspondingly formed lumen of the auxiliary-tube-adjoining end of the ureter tube and thus prevents undesired rotational movements of the mandrin within the ureter tube. Auxiliary tube and mandrin can be firmly connected in the end range, this connection, however, being releasable if required.
The invention described below may be used with arrangements according to DE-OS 39 00 738 as well as with arrangements according to DE-OS 38 24 244 and particularly also with arrangements which exhibit features of DE-OS 39 00 738 and of DE-OS 38 24 244.
To be sure in the embodiment according to FIG. 1 of DE-OS 39 00 738 it was possible, as a matter of principle, to inject upon withdrawal of the mandrin inner shaft through the mandrin outer shaft and by way of drainage canals located above the end of the mandrin outer shaft, an X-ray contrasting medium into the urethra and thus further into the renal pelvis outlet system. However, this was possible only incompletely since on the one hand the flow direction of the X-ray contrast medium had to change twice by 90.degree. in the process, and since particularly the X-ray contrasting medium had to find its way through the relatively narrow gap between ureter tube and ureter.